This document discusses neurotransmitters and receptors in the nervous system. It defines neurotransmitters as chemical substances that transmit nerve impulses between neurons through synapses. Neurotransmitters are synthesized in the presynaptic neuron, packaged into vesicles, released into the synaptic cleft when calcium enters during an action potential, bind to receptors, and are then inactivated. The document also defines receptors as proteins that receive chemical signals and cause a cellular response. Receptors are classified as exteroceptors, which respond to external stimuli, or interoceptors, which respond to internal stimuli. Common neurotransmitters and receptor types are also listed.

1. Human Anatomy and Physiology-II
Nervous system
(Neurotransmitters, Receptors)
Mr N.JEGAN
Associate Professor
K.M.COLLEGE OF PHARMACY.
MADURAI.

2. Content
1.Neurotransmitters
2. Receptors

3. Neurotransmitters

4. Neurotransmitters-Definition
Neurotransmitter is a chemical
substance that acts as a mediator for
the transmission of nerve impulse from
one neuron to another neuron through
a synapse.

5. Neurotransmitters
► Target cell may be a neuron or some
other kind of cell like a muscle or
gland cell.
► Necessary for rapid communication in
synapse.
► Neurotransmitters are packaged into
synaptic vesicles - presynaptic side of
a synapse.

6. PROPERTIES OF NEUROTRANSMITTERS
1) Synthesized in the presynaptic neuron
2) Localized to vesicles in the presynaptic neuron
3) Released from the presynaptic neuron under physiological
condition

7. 4) Rapidly removed from the synaptic cleft by uptake or
degradation
5) Presence of receptor on the post-synaptic neuron.
6) Binding to the receptor elicits a biological response

9. TYPES OF NEUROTRANSMITTERS

10. Action of Neurotransmitters
Step-I
Synthesis: Neurotransmitters are synthesized by the enzymatic
transformation of precursors.
Step-II
Storage: They are packaged inside synaptic vesicles.
Step-II
Release:
They are released from presynaptic terminal by exocytosis when
calcium enters axon terminal during an action potential .
It diffuse across the synaptic cleft to the postsynaptic membrane.

11. Step-IV
Binding: They bind to receptor proteins.
Step-IV
Inactivation:
The neurotransmitter is degraded either by being broken down
enzymatically, or reused by active reuptake.

13. Receptor

14. Receptor-Definition
Receptor is a protein molecule usually found embedded within the
plasma membrane surface of a cell that receives chemical signals from
outside the cell and when such chemical signals bind to a receptor, they
cause some form of cellular/tissue response.

15. CLASSIFICATION OF RECEPTORS
Generally, receptors are classified into two types:
A. Exteroceptors
B. Interoceptors

16. Exteroceptors
Exteroceptors are the receptors, which give response to stimuli arising from
outside the body.
Exteroceptors are divided into three groups:
1.Cutaneous Receptors or Mechanoreceptors- situated in the skin, response to
mechanical stimuli such as touch, pressure and pain
2. Chemoreceptors- Response to chemical stimuli e.g Taste
3. Telereceptors -Response to stimuli arising away from the body

19. INTEROCEPTORS
Interoceptors are the receptors, which give response to
stimuli arising from within the body.
1. Visceroceptors
Receptors situated in the viscera are called visceroceptors.
2. Proprioceptors
Proprioceptors are the receptors, which give response to change in
the position of different parts of the body.

21. Functions of Receptor

22. Thank you